The Ubuntu Security team suggests that contributors look into merging Debian security updates in community-supported packages. If you would like to help Ubuntu but are not sure where to start, this is a great way to do so. See the available merges and SecurityTeam/UpdateProcedures for details on preparing Ubuntu security updates. If you have any questions, feel free to ask in #ubuntu-hardened. To find out other ways of helping out, please see SecurityTeam/GettingInvolved.